In another part of the Island, Caliban is screaming and angry because he thinks that Prospero has send him spirits to provoke him. Hearing noises.
Trinculo saw him and wonders what is it. He thinks that if he take this creature to England, maybe he could make a lot of money of this dead creature, but the fear won and he lies next to him.
Stefano, drunker, saw them both, and thought that it was a four legged animal. He hears Caliban's unusual sounds, and thinks that if he could take this monster back to Naples maybe it would give him money and buy wine to Caliban.